Usually, a car head rest has a pair of stays which are removably inserted into respective stay guide members. Each of the stay guide members has a stopper provided on its periphery and engaged with a sleeve secured to a seat back frame, so that the stay guide member is prevented from rotation about the sleeve. In a prior art, the sleeve is formed by cutting a pipe to a predetermined length and then by providing by blanking a notch which is to be engaged by the stopper of the stay guide member. However, to prepare the sleeve with the notch formed therein, many steps are required, which causes the head rest to be expensive.